Banks



(No Model.)

G. FAIRBANKS.

Mechanism for Reversing Motionupon a, Single Screw. No. 236,941. Patented Jam-25 1881.

' I I FIG. WITNESSES. 4 INVENTOR MPEIERS. PNOTO-UTNOGRAPHER, WASHINGTON. D, C.

;. Z'UNIT-ED STATES PATENT OFFICE.

CRAWFORD M. FAIRBANKS, OF LINCOLN, RHODE ISLAND.

MECHANISM FOR FEVERSING MOTION UPON A SINGLE SCREW.

SPECIFICATION forming part of Letters Patent No. 236,941, dated January 25, 1881.

Application filed December 21, 1880. (No model.)

To all whom it may concern Be it known that I, CRAWFORD M. FAIR- BANKS, of Lincoln, in the State of Rhode Island, have invented a new and useful Mech-- anism for Reversing Motion upon a Single Screw; and I do hereby declare that the following specification, taken in connection with the drawings making a part of the same, is a full, clear. and exact description thereof.

Figure l is a view of my invention as adapted to a machine for stripping files. Fig. 2 is an end view of the feeding device working in one direction. Fig. 3 is an end view of same working in the opposite direction. Fig. 4 is a side view of same.

The object of my invention is to produce a reverse motion upon a single screw, and thus do away with the double screw, which is expensive in its manufacture, and which soon becomes worn and unfit for use; and it consists in the mechanism hereinafter described.

My invention, while applicable to a variety of machines, I have applied to machines for polishing file-blanks, in connection with which I shall proceed to describe it.

In the drawings, A, Fig. 1, is a carriage, upon which are placed the blanks B B. The carriage A is attached to the shaft 0 in such a manner as to admit of a longitudinal movement thereon, such movement being accomplished and also limited by a pin, D, attached to the carriage and traveling in the screwthread E.

F is a U-shaped frame, across the extended ends of which is a polishing-bar, not necessary to be shown in the accompanying drawings, which traverses the surfaces of the blanks B B. The frame F is connected by a rod, G, to the crank H upon the shaft I, motion being imparted to the latter in any desired way.

J is a cog-wheel, fixed to the end of the shaft 0.

K is a loose collar .upon the shaft 0, with a perpendicular projecting arm, L.

Attached to the end of the arm L is a horizontal rod, M, upon which works a sleeve, X, which is connected to the eccentric N upon the shaft I by the rod 0.

To the-outerend of the rod M is attached a pawl, I, having two arms, Q R, which alternately engage the ratchet or cog wheel J. The arms Q R are alternately depressed and raised through the action of the double arm Z, the spiral springs or a being employed to give a yielding pressure.

Upon the under side of the horizontal sleeve X are two inclined surfaces, meeting in a sharp edge at their-lower extremities, one or the other of which inclined surfaces rests upon a piston, S, supported and forced upward by a spring, T

Having now described the several parts of my invention, I will now proceed to describe its operation, commencing with the parts in the position shown in Figs. 1 and 2.

Motion bein gimparted to the crank B through the shaft I, a reciprocating motion is given to the frame F and its polishing-bar. As the shaft I rotates it acts upon the eccentric N, which, through itsrod 0, gives to the arm L and the parts attached thereto an oscillating movement. With each forward movement of the pawl the arm R engages the cog or ratchet wheel J, and turns it until the backward movement brings the arm back, when the same operation is repeated. -As the wheel J turns in the direction stated the screw-shaftG rotates, and the carriage A, through the aid of the pin D, traveling in the screw-thread E, moves along the shaft 0. This operation continues until the carriage A has reached the extreme of its movement in that direction and the pin D brings up at the end of the thread. As soon as the pin D reach es the end of the thread the shaft 0 can no longer rotate in the same direction, and the next forward movement of the eccentric-rod 0 turns the sleeve X, depresses the projecting edge formed by the coming together of the inclined surfaces, which forces down the piston S, overcoming the resistance of the spring T until the sleeve X rests upon its other inclined surface, as shown in Fig. 3. This change in the position of the sleeve X raises and disen gages the arm R of the pawl, and throws in the arm Q, as shown in Figs. 3 and 4, when each backward movement of the rod 0 will turn the ratchet-wheel J in the opposite direction, and cause the carriage A to travel back until it reaches its other Z, pawl P, ratchet-wheel J, collar K, with its [0 extreme, when the sleeve X will he brought arm L and spring-piston S, and the screwback to its former position, all in a manner shaft (3, the whole constructed and operating which will be readily understood, and the same substantially as described.

5 operation repeated.

What I claim as my invention, and desire FAIRBANKS to secure by Letters Patent, is Witnesses:

The combination of the shaft I, the eccen- WALTER B. VINCENT, tric N, rod 0, sleeve X, with its double arln JAMES J. NOLAN, Jr. 

